Media captionBasil McCrea said he is "instigating legal action" over the claims

The leader of Northern Ireland's newest party, NI21, has said he is taking unspecified legal action.

Basil McCrea was speaking after a very public falling-out between himself and deputy leader, John McCallister.

First, there was a clash over a last-minute decision to change the party's designation from "unionist" to "other" two days before polling day.

Then, allegations of inappropriate sexual activity were made against Mr McCrea, which he strongly denies.

Earlier, Mr McCallister had called for Mr McCrea to step aside as leader while an investigation was carried out into the allegations.

Mr McCallister claimed the party re-designation issue was an attempt to derail the investigation which he had instigated.

Speaking at the European election count on Monday at the King's Hall in Belfast, Mr McCrea said he was taking legal action but would not be drawn further.

Mr McCrea and Mr McCallister lead NI21, which they launched together in June 2013.

They left the Ulster Unionist Party to set up a new "confident, generous and progressive pro-UK party to step forward and build support for a modern Northern Ireland in the 21st century."

On polling day last week, Mr McCallister called for Mr McCrea to step aside while allegations of sexual impropriety on the part of Mr McCrea against former party worker, Ashleigh Murray, 23, are investigated.

Mr McCrea denies the allegations.

Amid turmoil within the party and the very public falling-out between Mr McCrea and his deputy leader NI21's European candidate Tina McKenzie resigned from the party executive and said she was quitting active politics.

In the local elections, NI21 took one seat.

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Media captionTina McKenzie says she has had a 'difficult few weeks' in politics

Speaking at the European election count on Monday, Mr McCrea said he had come to thank all the people that fought his party's campaign.

"I am not shy when it comes to talking about things but I cannot say anything because I am instigating legal action," he said.

"My lawyers have said to me; 'You cannot speak'. It's an instruction and those matters will de dealt with through the proper channels."

Earlier, Mr McCallister said he spoke to Mr McCrea on the telephone for 25 minutes on Saturday.

He said he told him that no party leader could function "with all this going on".

Disagreement arose between the men last week after the party re-designated as 'other' rather than 'unionist'.

Mr McCallister alleged that decision was an attempt to derail an investigation into the claims of inappropriate sexual activity by Mr McCrea.

Mr McCrea has denied any wrongdoing.

Speaking to BBC News NI on Monday, Mr McCallister said: "My focus over recent weeks was, and still is, on getting the independent investigation into these allegations and issues.

"Getting that and only that, is my prime focus and continues to be for the next week or however long that takes to complete."

'Difficult days'

He said he rang his party leader "mainly to ask how he is".

"Obviously, it has been a difficult few days for Basil and his family on a personal level," he said.

"I then... repeated that call that no party leader can function with all of this going on in the background, even to step aside without prejudice, to let at least the party function.

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Media captionNI21 deputy leader John McCallister

"We have to find, when this report comes out, mechanisms of, if there are recommendations, how we deal with that, how we take it forward.

"Of course, I'll be sharing the report with the Northern Ireland Assembly as well, to see what issues or lessons are there for them."

Asked if Mr McCrea said he would step aside, Mr McCallister said: "He neither said he would or he wouldn't. We talked about it, but he didn't give a direct answer.

"He seemed remarkably chirpy on the phone, considering all," he said.

Mr McCallister said he had no control over the timing of the controversy. He said the issue of re-designation was "very much about stopping this investigation going forward".

He said the investigation could not be moved aside while the party dealt with issues such as recent resignations.

Asked about his intentions for the future, Mr McCallister said he was going to complete his duty of care to the staff and members of the party.